Novel polymer composition

ABSTRACT

A polymer composition in which an organic polymer and carbon fiber are strongly combined and a process for producing the polymer composition by the electrolytic polymerization of a reactive monomer using the carbon fiber as an electrode, which process is characterized in that the polymerization is carried out by adding an aliphatic epoxy compound, alicyclic epoxy compound, organic titanate compound, or vinylsilane compound, as part or all of the reactive monomer.

This invention relates to a process for producing a novel polymer composition in which carbon fiber (hereinafter abbreviated as "CF") and an organic polymer are strongly combined, by the electrolytic polymerization method.

A process for producing a metal-organic polymer composition is known which comprises electrolytic polymerization of a reactive monomer using a metal such as iron, copper, or silver as an electrode. However, from the industrial point of view, there is little possibility of putting this process to practical use because of a low polymerization activity of the monomer and a markedly limited amount of the polymer deposited on the metal.

For example; Subramanian, R. V. and Jakubowski, J. J. reported on "Electrolytic polymerization behavior and physical properties of vinyl monomers and Azyrydine compounds" {Polym. Eng. Sci., 18, p.590 (1978)} and on "Electrochemical coating with phosphorous-containing organic titanate compound" [Composites, 161, (1980)]; Japanese Patent Application Laid-Open No. 72496/74 disclosed that electrolytic graft polymerization of a vinyl monomer on CF improves the tensile strength by 10-15%; and Japanese Patent Application Laid-Open No. 122894/78 disclosed that the inter-laminar shear strength (ILSS) of a CF composite is improved by electrolytic polymerization of a vinyl monomer in the presence of a peroxide using the CF as cathode.

However, these prior techniques were unsuccessful in solving the above noted problems.

In view of the above, the present inventors made intensive studies and found out that, in the production of a CF-organic polymer composition by electrolytic polymerization of a reactive monomer using an electrode of electrically conductive CF, the use of an aliphatic epoxy compound, alicyclic epoxy compound, organic titanate compound, or vinylsilane compound as part or all of the reacctive monomer results in a strikingly improved polymerization activity of reactive monomer and a novel polymer composition, unobtainable by the prior art process, in which the organic polymer is coupled in a large amount and strongly with the electrode CF and has a good sizing effect. Based on this finding, this invention has been accomplished.

Up to now, research and development have been extensively made from composite materials which are products of combining two or more materials for supplying deficiencies in the properties of the individual materials and for creating a new beneficial function. Under such circumstances, improvements in a wide variety of properties for example, mechanical strength, elastic modulus, heat distortion temperature, and electric properties have been reported concerning the formation of composite from CF which is useful as filler for reinforcement of organic polymers. These composites, however, are deficient in interfacial affinity such as compatibility or adhesion between CF and another component, viz. organic polymer, since these components distinctly differ from each other in properties, so that a sufficient combining effect cannot be exhibited. This is the present situation of the art.

For the purpose of improving CF composites in this respect, attempts have been made to enforce the interfacial affinity between organic polymer and CF, which include the graft polymerization of vinyl monomer on the surface of CF oxidized by treatment with an inorganic acid and the grafting of organic polymer onto CF irradiated with high energy radiation. However, these attempts have significant problems in the aspect of practical applications, such as the complication of operating steps and a remarkable increase in the production cost.

It is the primary object of this invention to provide a process for producing a polymer composition which solves the above noted problems.

Thus, this invention provides a process for producing a polymer composition, wherein an organic polymer is strongly bonded to CF, characterized by using an aliphatic epoxy compound, alicyclic epoxy compound, organic titanate compound, or vinylsilane compound as a part or all of reactive monomer in the process wherein the reactive monomer is electrolytically polymerized using the CF as an electrode.

When the electrolytic polymerization of reactive monomer is conducted even in the presence of a supporting electrolyte, the percentage of polymerization is generally on a considerably low level even after a long period of polymerization. On the contrary, a quite specific polymerization activity is brought about, according to this invention, by using the above cited monomer as a part or all of the reactive monomer, and a large amount of polymer is formed in several seconds on the surface of CF with such a high percentage of polymerization as to be practically useful and additionally the polymer has a good sizing effect, thereby much improving the CF binding state.

Another feature of this invention is that the interaction between CF and the polymer formed according to the process of this invention is stronger than an adhesion such as simple adsorption or the like. Thus the polymer firmly binds the CF, exerting an excellent sizing effect.

An illustration of the form of carrying out this invention is as follows: an electrolytic solution is prepared by dissolving a reactive monomer and a supporting electrolyte in a solvent. A CF roving is immersed in the electrolytic solution and D.C. voltage is applied between the CF roving and the electrolytic solution for a prescribed period to polymerize the reactive monomer on the CF surface. Thus, a large amount of uniform polymer can be formed from the reactive monomer with a high percentage of polymerization to adhere strongly to the CF surface. For this polymerization, the presence of the above four components is an essential condition. However, the supporting electrolyte need not always be present in the electrolytic solution during the electrolytic polymerization. That is, a similar polymer composition can also be obtained by using the CF pretreated with the supporting electrolyte, without adding the supporting electrolyte to the electrolytic solution.

Cations which can constitute the supporting electrolyte used in this invention are alkali metal ions (Li⁺, Na⁺, K⁺, Rb⁺, and Cs⁺); NH₄ ⁺, and quaternary alkyl ammonium ions of the formula R₄ N⁺, wherein R₄ represents lower alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, n-hexyl, or the like; and sometimes include alkaline earth metal ions and as organic cations; substituted quaternary alkylammonium ions of the formula R_(n) 'R"_(4-n) N⁺, wherein R' represents alkyl, R" represents aryl or aralkyl, and n represent an integer of 1-4; quaternary phosphonium ions (R₄ P⁺); and tertiary sulfonium ions (R₃ S⁺).

Anions which can constitute the supporting electrolyte are halogen ions (Cl⁻, Br⁻, and I⁻), sulfate ion (SO₄ ²⁻), nitrate ion (NO₃ ⁻), perchlorate ion (ClO₄ ⁻), various sulfonate ions, various carboxylate ions, tetrafluoroborate ion (BF₄ ⁻), and so forth.

Accordingly, various salts can be formed by combining the above-cited cations and anions and can be used as supporting electrolytes in this invention. It is a matter of course that bases from the above cations and acids from the above anions can also be used as the supporting electrolyte.

Thus, compounds of, for example, the following formulae, can be used as supporting electrolytes in this invention: LiCl, NaClO₄, NaNO₃, KClO₄, EtNClO₄, n-Bμ₄ NClO₄, n-Bμ₄ NI, NaI, Et₄ NBr, Et₄ NI, LiClO₄, NaBF₄, KCl, KI, NH₄ Cl, NH₄ NO₃, KNO₃, NaClO₄, LiNO₃, HCl, H₂ SO₄, ZnCl₂, NaOAc, NH₄ OAc, KOH, NH₄ Cl, and LiBr.

The specific reactive compound used in this invention has two or more functional groups in the molecule, which act as active sites for making strong bonds between the polymer and the CF surface and for reacting with the matrix resin. Preferred reactive compounds are:

(1) Aliphatic epoxy compounds represented by the general formula ##STR1## wherein; R₁, R₂, R₃, and R₄ represent hydrogen, C₁ -C₂₀ alkyl, phenyl, substituted phenyl having C₁ -C₂₀ alkyl, or halogen; and n represents an integer of 0-50, preferably 0-20;

(2) alicylic epoxy compounds represented by the general formula ##STR2## wherein; R₅ represents ##STR3## (R₇ represents C₁ -C₂₀ alkylene); and R₆ represents C₁ -C₃₀ alkylene;

(3) alicyclic epoxy compounds represented by the general formula ##STR4## wherein R₈ represents C₁ -C₃₀ alkylene;

(4) organic titanate compounds represented by the general formula

    Ti(O-R.sub.9).sub.4                                        (IV)

wherein R₉ represents C₁ -C₅₀ alkyl;

(5) organic titanate compounds represented by the general formula ##STR5## wherein R₁₀ represents hydrogen or C₁ -C₄₀ alkyl and R₁₁ represents C₁ -C₄₀ alkyl; and

(6) vinylsilane compounds represented by the general formula ##STR6## wherein; R₁₂ represents hydrogen, C₁ -C₂₀ alkyl, phenyl, substituted phenyl having C₁ -C₂₀ alkyl, or halogen; R₁₃ represents (CH₂)_(m) or COO(CH₂)_(Q) (m is an integer of 0-30 and Q is an integer of 0-20); and R₁₄ represents hydrogen, C₁ -C₁₅ alkyl, or --Y--O--Z (Y is C₁ -C₁₅ alkylene and Z is C₁ -C₁₅ alkyl).

Examples of the aliphatic epoxy compound are ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ethers, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, neopentyl glycol diglycidyl ether, glycerol polyglycidyl ethers, trimethylolpropane polyglycidyl ethers, pentaerythritol polyglycidyl ethers, diglycerol polyglycidyl ethers, and sorbitol polyglycidyl ethers. These are favorable in marked sizing effect and high electrolytic polymerization activity.

Examples of the alicyclic epoxy compounds are bis-epoxycyclohexylcarboxylates, bis-epoxycyclohexyldicarboxylates, and bis-epoxycyclohexyldioxanes. These are favorable in marked sizing effect and high polymerization activity.

Examples of the organic titanate compound are tetraalkoxytitaniums and monoalkoxytitaniumtrialkylates. These are favorable in marked sizing effect and high polymerization activity.

Examples of the vinylsilane compound are vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltributoxysilane, vinyl-tris(β-methoxymethoxy)silane, vinyl-tris(β-methoxyethoxy(silane, vinyl-tris(β-methoxypropoxy)silane, vinyl-tris(β-methoxybutoxy)silane, γ-methacryloxymethyltrimethoxysilane, γ-methacryloxyethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxybutyltrimethoxysilane. Particularly, vinyltriethoxysilane, vinyl-tris(β-methoxyethoxy)silane, and γ-methacryloxypropyltrimethoxysilane are favorable in marked sizing effect and high polymerization activity.

CF's used in this invention include, for example; those of high tenacity and high modulus of elasticity produced from polyacrylonitrile or copolymer thereof; those produced from high-temperature-cracked petroleum pitch, coal tar pitch, or coal-depolymerized product; and those produced by the vapor deposition method. either carbonaceous CF or graphitic CF can be applied. These various types of CF may or may not have been subjected to the usual surface-oxidizing treatment.

As to the form of CF, rovings in the form of long fibers having a fiber diameter of 0.1-5μ are desirable. When such CF is used, a very high sizing effect is obtained. CF of 5μ or less in fiber diameter, which has been conventionally used, is liable to undergo fuzzing and monofilament-break. Accordingly, it is very important for the conventional CF to be protected with a size. However, because of its poor property for handling, its uniform sizing is extremely difficult. Nevertheless, according to the process of this invention, a uniform sizing effect can be achieved without inflicting any damage on CF, this being a great advantage of this invention.

The reactive comonomer used in this invention is not particularly limited. For instance, usual radical-polymerizable vinyl monomers can be used.

Examples of such vinyl monomers are acrylic acid and esters thereof, methacrylic acid and esters thereof, styrene, acrylonitrile, vinyl acetate, acrylamide, maleic anhydride, vinylpyrrolidone, and vinylpyridine.

The compositions according to this invention are all obtained in bundled form having a good interfacial adhesive property and good processability.

In this invention, the concentration of the reactive compound in the electrolytic solution ranges approximately from 0.05 to 100%, preferably from 0.1 to 50%, particularly preferably from 0.5 to 30%, by weight. The weight ratio of the reactive monomer or mixture thereof to the used CF can be varied over a wide range, that is, approximately from 500:1 to 1:500, preferably from 50:1 to 1:50.

The amount of the solvent ranges aproximately from 0.0001 to thousands times, preferably from 0.01 to 100 times, based on the total weight of CF and monomer.

Any solvent may be employed in this invention unless it hinders the achievement of the object of this invention. Suitable solvents include, for example, water; alcohols such as methanol, ethanol, glycerol, and cellosolves; ethers such as diethyl ether, tetrahydrofuran, and 1,4-dioxane; nitriles such as acetonitrile, butyloacetonitrile, and benzoacetonitrile; amines such as ammonia, ethylenediamine, and pyridine; amides such as formamide, dimethylformamide, and dimethylacetamide; sulfur compounds such as sulfur dioxide, dimethylsulfoxide, and sulfolane; and other miscellaneous solvents such as acetone, dichloromethane, nitromethane, nitrobenzene, and propylene carbonate.

The concentration of the supporting electrolyte used in the electrolytic solution ranges from 0.01 to 30%, preferably from 0.1 to 5%, by weight.

The electrolytic polymerization is effected by passing D.C. current between the CF and the electrolytic solution containing the reactive monomer, where the current density ranges generally from 0.01 to 20 A/dm², preferably from 0.1 to 2 A/dm², and the voltage is generally about 5-about 25 V. The current density, when excessively low, results in unfavorably low rate of polymerization and, when excessively high, undesirably causes degradation of the CF. The reaction period ranges approximately from 0.1 second to 5 hours, and the reaction temperature approximately from -50° to 100° C., preferably from 0° to 80° C. The reaction temperatures in individual cases are suitably chosen depending upon the reactive monomer used, where it is important to choose such temperatures as to supress the thermal polymerization to a negligible degree. If the electrolytic polymerization is carried out at such high temperatures as to cause marked thermal polymerization, the cohesive strength and uniformity of the resulting composition will be impaired. In this invention, the produced composition can be dried in a wide temperature range of approximately from 10° to 300° C., preferably from 30° to 200° C.

The interaction between the CF surface and the polymer in the novel polymer composition of this invention is stronger than the physical interaction in the cases of simple van der Waals adsorption and the like. This is supported by the fact that a large amount of unextracted polymer is found after extraction of the present composition with a good solvent of the polymer.

The novel polymer composition of this invention is useful for a wide variety of applications, e.g. aircraft, space vehicles, sporting and recreation goods, automobiles, audio, and general industrial uses.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawing is an illustration showing a preferred embodiment of the device for electrolytic polymerization on a CF roving according to this invention. Numerals in the drawing denote the following:

1--Electrode rollers (made of copper)

2--Guide rollers (made of glass)

3--CF roving

4--Electrolytic solution

5--Reaction vessel (made of stainless steel)

6--DC generator

7--Rheostat

8--Ammeter

This invention is illustrated in more detail with reference to the following Examples, wherein "parts" are all by weight.

EXAMPLES 1-2 AND COMPARATIVE EXAMPELS 1-3

A roving of PAN-derived high-tenacity CF (made by Mitsubishi Rayon Co., Ltd.) was set in an electrolytic polymerization reactor (made of stainless steel), as shown in the drawing, provided with copper electrode rollers and glass guide rollers. An electrolytic solution prepared by dissolving 50 g of a polyethylene glycol (n=4) diglycidyl ether (tradename: Denacol EX-821, made by Nagase Sangyo Co., Ltd.) as an aliphatic epoxy compound and 25 g of sodium nitrate as a supporting electrolyte in 500 g of DMF was poured into the reactor to immerse the CF roving.

Then, direct current was supplied from a D.C. generator to flow between the CF which is made to act as anode, and the electrolytic solution, thereby carrying out the electrolytic polymerization of the epoxy compound at room temperature for one hour. During the electrolysis, the current density was adjusted to 0.27 A/dm² by means of a rheostat.

The product roving was thoroughly washed with DMF and dried in a stream of 100° C. hot air. Then, the binding state of the CF and the amount of polymer deposit on the CF were examined, where the latter was determined by weighing.

The same polymerization procedure was repeated by using a mixed monomer consisting of 25 g EX-821 and 25 g of methyl methacrylate (MMA) and the product was examined as the above.

For the purpose of comparison, electrolytic polymerization and product evaluation were conducted in the same manner but using separately MMA, which is a usual vinyl monomer; polyethylene glycol (average molecular weight 300), which has no epoxy functional group; and a mixture of MMA and the same polyethylene glycol in place of the reactive monomer of this invention.

Results of these Examples and Comparative Examples are shown in Table 1. It is evident from the Table that; as in Comparative Example 2, polyethylene glycol itself exhibits no polymerization activity and as in Comparative Example 1, the CF binding state is considerably inferior and the amount of the polymer deposit on the CF is extremely limited; in contrast to this, according to the production process of this invention, an excellent CF binding state and a much increased amount of polymer deposit are obtained, thus markedly improving the practical value of the product composition.

                  TABLE 1                                                          ______________________________________                                                  Denacol*.sup.1      Polyethylene                                                                            CF*.sup.4                                         EX-821    MMA*.sup.2                                                                               glycol*.sup.3                                                                           (part)                                   ______________________________________                                         Example 1                                                                               50        --        --       0.123                                    Example 2                                                                               25        25        --       "                                        Comparative                                                                             --        50        --       "                                        Example 1                                                                      Comparative                                                                             --        --        50       "                                        Example 2                                                                      Comparative                                                                             --        25        25       "                                        Example 3                                                                      ______________________________________                                                Supporting         Reaction product*.sup.6                                       electrolyte                Amount*.sup.8                                       Sodium      Solvent  CF*.sup.7                                                                            of polymer                                          nitrate     DMF*.sup.5                                                                              binding                                                                              deposit on                                          (parts)     (parts)  state CF (parts)                                 ______________________________________                                         Example 1                                                                               2.5         500      ⊚                                                                     72                                         Example 2                                                                               "           "        ⊚                                                                     69                                         Comparative                                                                             "           "        x     7                                          Example 1                                                                      Comparative                                                                             "           "        xx    0                                          Example 2                                                                      Comparative                                                                             "           "        x     2                                          Example 3                                                                      ______________________________________                                          Note:                                                                          *.sup.1 An aliphatic epoxy compound made by Nagase Sangyo Co., Ltd.            *.sup.2 MMA: Methyl methacrylate                                               *.sup.3 An aliphatic ether                                                     *.sup.4 A roving of PANderived hightenacity CF made by Mitsubishi Rayon        Co., Ltd.                                                                      *.sup.5 DMF: N,N--Dimethylformamide                                            *.sup. 6 Reaction conditions                                                   Temperature: 25° C.                                                     CF polarity: Positive (anode)                                                  Current density: 0.27 A/dm.sup.2                                               Voltage: 20 V                                                                  Period of electrolysis: 60 minutes                                             *.sup.7 CF binding state                                                       ⊚ very good                                                     x inferior                                                                     xx much inferior                                                               *.sup.8 Based on 100 parts of charged CF.                                

EXAMPLES 3-7

In the same manner as in Example 1 but using separately aliphatic epoxy compounds: Denacol's EX-810, EX-840, EX-314, EX-611, and EX-321 as the reactive monomer, in place of Denacol EX-821, electrolytic polymerization was conducted, and amounts of polymer deposit of CF were examined. Results thereof are shown in Table 2 comparing with those of Example 1.

                  TABLE 2                                                          ______________________________________                                                                 Sup-                                                                           porting       Amount                                   Reactive                elec-         of*.sup.1                                monomer                 trolyte Sol-  polymer                                  Aliphatic   A-              Sodium                                                                               vent  deposit                                epoxy       mount   CF      nitrate                                                                              DMF   on CF                                  compound    (parts) (part)  (parts)                                                                              (parts)                                                                              (parts)                                ______________________________________                                         Example                                                                              Denacol*.sup.2                                                                           50      0.123 2.5   500   72                                   1     EX-821                                                                   Example                                                                              Denacol*.sup.3                                                                           "       "     "     "     61                                   3     EX-810                                                                   Example                                                                              Denacol*.sup.4                                                                           "       "     "     "     79                                   4     EX-840                                                                   Example                                                                              Denacol*.sup.5                                                                           "       "     "     "     42                                   5     EX-314                                                                   Example                                                                              Denacol*.sup.6                                                                           "       "     "     "     50                                   6     EX-611                                                                   Example                                                                              Denacol*.sup.7                                                                           "       "     "     "     55                                   7     EX-321                                                                   ______________________________________                                          Notes:                                                                         *.sup.1 Based on 100 parts of charged CF.                                      *.sup.2 Denacol EX821:                                                         ##STR7##                                                                                                                                                      *.sup.3 Denacol EX810:                                                         ##STR8##                                                                                                                                                      *.sup.4 Denacol EX840:                                                         ##STR9##                                                                                                                                                      *.sup.5 Denacol EX314:                                                         ##STR10##                                                                                                                                                     *.sup.6 Denacol EX611:                                                         ##STR11##                                                                                                                                                     *.sup.7 Denacol EX321:                                                         ##STR12##                                                                

As is evident from Table 2, the amount of polymer deposited on CF was considerably large in the cases of EX-821, EX-810, and EX-840 and was on somewhat lower levels in the cases of EX-314, EX-611, and EX-321.

In the next place, the percentage of polymer extracted from the product was determined on the CF-polymer composites obtained in Examples 1-7, by weighing out about 0.1 g of each composition together with a cylindrical filter paper and subjecting the composition sample to Soxhlet extraction with chloroform for 24 hours. For comparison, the same test was conducted on a composition (Comparative Example 4) prepared by a bulk polymerization in the presence of the same CF roving using a common radical polymerization initiator. Results of the test are shown in Table 3. As can be seen therefrom, whereas the polymer in the composition of Comparative Example 4 was completely extracted out by the 24-hour extraction, very low percentages of polymers were extracted from the compositions prepared according to this invention, that is, most of the polymers were firmly bonded to CF without being extracted.

                  TABLE 3                                                          ______________________________________                                                                        Percentage                                                            Amount   of polymer                                                            of       extracted                                                             polymer  with                                                                  deposit  chloroform                                                            on CF    for                                             Polymerization process                                                                               (parts)*.sup.2                                                                          24 hours                                        ______________________________________                                         Example                                                                               Process of this invention using                                                                   72       3                                           1      Denacol EX-821 as reactive                                                     monomer                                                                 Example                                                                               Process of this invention using                                                                   69       4                                           2      a mixture of Denacol EX-821                                                    and MMA as reactive monomer                                             Example                                                                               Process of this invention using                                                                   61       3                                           3      Denacol EX-810 as reactive                                                     monomer                                                                 Example                                                                               Process of this invention using                                                                   79       3                                           4      Denacol EX-840 as reactive                                                     monomer                                                                 Example                                                                               Process of this invention using                                                                   42       5                                           5      Denacol eX-314 as reactive                                                     monomer                                                                 Example                                                                               Process of this invention using                                                                   50       6                                           6      Denacol EX-611 as reactive                                                     monomer                                                                 Example                                                                               Process of this invention                                                                         55       7                                           7      using Denacol EX-321                                                           as reactive monomer                                                     Com-   Bulk polymerization using                                                                         95       100                                         parative                                                                              DDS*.sup.1 as initiator                                                 Example                                                                        ______________________________________                                          Notes:                                                                         *.sup.1 DDS: Diaminodiphenylsulfone                                            *.sup.2 Based on 100 parts of charged CF                                 

EXAMPLE 8

Electrolytic polymerization was conducted in the same manner by using different kinds of CF. Results of evaluating the product composition are shown in Table 4.

                  TABLE 4                                                          ______________________________________                                                                                Percentage                                                              Amount of polymer                                                       Average                                                                               of*.sup.3                                                                             extracted                                                        diameter                                                                              polymer                                                                               with                                                    Nature   of mono-                                                                              deposit                                                                               chloro-                                                 of       filament                                                                              on CF  form for                                No.  CF         fiber    (μ) (parts)                                                                               24 hours                                ______________________________________                                         1    From pitch*.sup.1                                                                         Carbo-   12.5   75     3                                            (T-101S)   naceous                                                        2    From pitch*.sup.1                                                                         Graphitic                                                                               "      70     5                                            (T-201S)                                                                  3    From PAN*.sup.2                                                                           Carbo-   "      72     3                                            (HT)       naceous                                                        4    From PAN*.sup.2                                                                           Graphitic                                                                               "      71     6                                            (HM)                                                                      ______________________________________                                          Notes:                                                                         *.sup.1 Krecatow made by Kureha Chem. Ind. Co., Ltd.                           *.sup.2 Made by Mitsubishi Rayon Co., Ltd.                                     *.sup.3 Conditions of electrolytic polymerization CF, 0.123 part; Sodium       nitrate, 25 parts; DMF, 500 parts; EX821, 50 parts                       

As can be seen from Table 4, in the process of this invention, no dependency on the kind of CF was observed of polymerization activity, amounts of polymer deposited on CF were generally satisfactory, and percentages of polymer extracted from the product composition were low, that is, most of the polymers were firmly bonded to CF without being extracted.

EXAMPLE 9

Electrolytic polymerization was conducted in the same manner as in Example 1 but using each reactive comonomer (25 g) shown in Table 5 together with Denacol EX-821 (25 g). Results of evaluating the product composition are shown in Table 5.

                                      TABLE 5                                      __________________________________________________________________________                                            Amount of*.sup.5                                        Supporting       Polarity of                                                                          polymer                                 Reactive comonomer                                                                             electrolyte                                                                          PAN-  Solvent                                                                             CF during                                                                            deposit on                              Run        Amount                                                                              NaNO.sub.3                                                                           derived CF                                                                           DMF  elec- CF                                      No.                                                                               Kind    (parts)                                                                             (parts)                                                                              (part)                                                                               (parts)                                                                             trolysis                                                                             (parts)                                 __________________________________________________________________________     1  MMA     25   2.5   0.123 500  anode 80                                      2  ST*.sup.1                                                                              "    "     "     "    "     58                                      3  Vinyl   "    "     "     "    "     65                                         acetate                                                                     4  BuA*.sup.2                                                                             "    "     "     "    "     72                                      5  MAA*.sup.3                                                                             "    "     "     "    "     70                                      6  GMA/MAA*.sup.4                                                                         "    "     "     "    "     95                                      7  GMA/BuA "    "     "     "    "     90                                      __________________________________________________________________________      Notes:                                                                         *.sup.1 ST: Styrene monomer                                                    *.sup.2 BuA: nButyl acrylate                                                   *.sup.3 MAA: Methacrylic acid                                                  *.sup.4 GMA: Glycidyl methacrylate                                             *.sup.5 Based on 100 parts of charged CF.                                

Weight ratio of one comonomer to the other in the run Nos. 6 and 7 was 50:50.

As is evident from Table 5, any usual vinyl monomer radical-polymerizable can be used as a reactive comonomer in this invention.

EXAMPLE 10

A roving (0.123 g) of PAN-derived CF (HT, made by Mitsubishi Rayon Co., Ltd.) was immersed in a solution prepared by dissolving 250 g of sodium nitrate as a supporting electrolyte in 500 g of demineralized water. After being thoroughly dried, the treated CF was all immersed in an electrolytic solution (50 g of Denacol EX-821 in 500 g of DMF) contained in the reactor of the same electrolytic polymerization apparatus as used in Example 1. Then, direct current from the D.C. generator was flowed between the CF acting as anode and the electrolytic solution, thereby carrying out the electrolytic polymerization at room temperature for one hour. During the electrolysis, the current density was adjusted to 0.27 A/dm² by means of the rheostat.

The product composition was evaluated in the same manner as in Example 1. The results showed that the amount of polymer deposit on the CF was 60 parts and the polymer produced from the reactive monomer was bonded uniformly and firmly to the CF surface.

EXAMPLE 11

A unidirectional composite was prepared from a CF-polymer composition obtained from a mixture of 1,000 parts of Denacol EX-821, 24.6 parts of CF, 50 parts of sodium nitrate and 100,000 parts of DMF according to the present invention and a general-purpose epoxy resin of bisphenol A type, and was shaped into test pieces, which were then measured for mechanical properties such as strand strength, inter-laminar shear strength, and flexural strength. For comparison, another unidirectional composite (simple blend) was similarly prepared by using untreated CF and evaluated. Results are shown in Table 6.

                  TABLE 6                                                          ______________________________________                                                    Mechanical properties                                                                       Inter-*.sup.1                                                                  laminar                                                             Strand     shear    Flexural*.sup.1                               Unidirection strength   strength strength                                      composite    kg/mm.sup.2                                                                               kg/mm.sup.2                                                                             kg/mm.sup.2                                   ______________________________________                                         Blend of CF-polymer                                                                         404        9.90     189.2                                         composition of this                                                            invention with                                                                 epoxy resin                                                                    Simple blend of                                                                             340        7.30     148.1                                         untreated CF with                                                              epoxy resin                                                                    ______________________________________                                          Note:                                                                          *.sup.1 CF content 60 vol. %                                             

Table 6 indicates that the CF-polymer composition of this invention exhibits excellent mechanical properties in practical applications.

EXAMPLES 12-13 AND COMPARATIVE EXAMPLES 5-7

A roving of PAN-derived high-tenacity CF was set in the stainless steel reactor of an electrolytic polymerization apparatus, as shown in the drawing, provided with electrode rollers and guide rollers. An electrolytic solution prepared by dissolving 50 g of bis(3,4-epoxy cyclohexyl)methyl adipate as an alicyclic epoxy compound and 25 g of sodium nitrate as a supporting electrolyte in 500 g of DMF was poured into the reactor to immerse the CF roving.

Then, direct current from a D.C. generator was flowed between the CF as anode and the electrytic solution, thereby carrying out the electrolytic polymarization at room temperature for one hour. During the electrolysis, the current density was adjusted to 0.27 A/dm² by means of a rheostat.

The product roving was thoroughly washed with DMF and dried in a stream of 100° C. hot air. Then, the binding state of the CF and the amount of polymer deposited on the CF were examined, where the latter was determined by weighing.

In the same manner, electrolytic polymerization was carried out by using a mixture of 25 g of the above alicyclic epoxy compound and 25 g of methyl methacrylate (MMA) and the product was evaluated.

For comparison, electrolytic polymerization and product evaluation were conducted in the same manner but using separately MMA, which is a usual vinyl monomer; ethyl glycidate, ##STR13## which is a noncylic monofunctional aliphatic epoxy compound; and a mixture of MMA and ethyl glycidate; as a reactive monomer.

Results of these Examples and Comparative Examples are shown in Table 7. As is evident from Table 7, the CF binding state is inferior and the amount of polymer deposited on CF is extremely limited, in Comparative Examples 5, 6, and 7; in contrast to this, an excellent CF binding state and a much increased amount of polymer deposit are obtained, according to the process of this invention, thus markedly improving the practicality.

                                      TABLE 7                                      __________________________________________________________________________                              Supporting                                            Reactive monomer         electrolyte                                                                               Reaction product*.sup.6                    (parts)                  Sodium                                                                               Solvent                                                                             CF*.sup.7                                                                          Amount of*.sup.8                       ERL-*.sup.1     Ethyl*.sup.3                                                                        CF*.sup.4                                                                          nitrate                                                                              DMF*.sup.5                                                                          binding                                                                            polymer deposit                        4299       MMA*.sup.2                                                                          glycidate                                                                           (part)                                                                             (parts)                                                                              (parts)                                                                             state                                                                              on CF (parts)                          __________________________________________________________________________     Example 12                                                                           50   --   --   0.123                                                                              2.5   500  ⊚                                                                   105                                    Example 13                                                                           25   25   --   "   "     "    ⊚                                                                   88                                     Compara-                                                                             --   50   --   "   "     "    x    3                                     tive                                                                           Example 5                                                                      Compara-                                                                             --   --   50   "   "     "    x    5                                     tive                                                                           Example 6                                                                      Compara-                                                                             --   25   25   "   "     "    xx   4                                     tive                                                                           Example 7                                                                      __________________________________________________________________________      Notes:                                                                         ##STR14##                                                                                                                                                     *.sup.2 MMA: Methyl methacrylate                                               ##STR15##                                                                                                                                                     *.sup.4 PANderived hightencity CF made by Mitsubishi Rayon Co., Ltd.           *.sup.5 DMF: N,Ndimethylformamide                                              *.sup.6 Reaction conditions                                                    Temperature: 25° C.                                                     CF polarity: Positive (anode)                                                  Current density: 0.27 A/dm.sup.2                                               Voltage: 20 V                                                                  Period of electrolysis: 60 minutes                                             *.sup.7 CF binding state                                                       ⊚ very good                                                     X inferior                                                                     XX much inferior                                                               *.sup.8 Based on 100 parts of charged CF.                                

EXAMPLES 14-16

Polymerization was conducted in the same manner as in Example 12 but using separately the alicylic epoxy compounds shown in Table 8 as an reactive monomer, and amounts of polymer deposited on CF were examined. Results there of together with those of Example 12 are shown in Table 8.

                  TABLE 8                                                          ______________________________________                                         Reactive               Sup-                                                    monomer                porting        Amount                                   Alicy-                     electro-     of*.sup.1                              clic                       lyte   Sol-  polymer                                epoxy      A-              Sodium vent  deposit                                com-       mount   CF      nitrate                                                                               DMF   on CF                                  pound      (parts) (part)  (parts)                                                                               (parts)                                      ______________________________________                                         Example                                                                               A*.sup.2                                                                               50      0.123 2.5    500   105                                  -12                                                                            Example                                                                               B*.sup.3                                                                               "       "     "      "     101                                  -14                                                                            Example                                                                               C*.sup.4                                                                               "       "     "      "      97                                  -15                                                                            Example                                                                               D*.sup.5                                                                               "       "     "      "      90                                  -16                                                                            ______________________________________                                          Notes:                                                                         *.sup.1 Based on 100 parts of charged CF.                                      *.sup.2 A: Bis [(3,4epoxy cyclohexyl)methyl] adipate                                                                                                          ##STR16##                                                                                                                                                     *.sup.3 B: 2(3,4-Epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-m-dioxan                                                                                     ##STR17##                                                                                                                                                     *.sup.4 C: (3,4Epoxycyclohexyl)methyl 3,4epoxy-cyclohexanecarboxylate                                                                                         ##STR18##                                                                                                                                                     *.sup.5 D: Vinylcyclohexene dioxide                                                                                                                           ##STR19##                                                                

As can be seen from Table 8, the amount of polymer deposited on CF was on high levels for both the polyfunctional alicyclic epoxy compounds.

Then, the percentage of polymer extraction from the product was determined on the CF-polymer compositions obtained in Examples 12-16, by weighing about 0.1 g of each composition together with a cylindrical filter paper and subjecting the composition sample to a Soxhlet extraction with chloroform for 24 hours. For comparison, the same test was conducted on a composition (Comparative Example 8) prepared by a bulk polymerization in the presence of the same CF roving using a common polymerization initiator. Results of the tests are shown in Table 9. Therefrom it can be seen that, whereas the polymer in the composition of Comparative Example 8 was completely extracted by the 24 hour-extraction, those in the compositions obtained by the process of this invention were extracted in low percentages, that is, most of the polymers were firmly bonded without being extracted.

                                      TABLE 9                                      __________________________________________________________________________                                    Percentage of                                                       Amount of polymer*.sup.1                                                                  polymer extracted                                                   deposited on CF                                                                           with chloroform                                 Polymerization process                                                                             (parts)    for 24 hours                                    __________________________________________________________________________     Example                                                                             Process of this invention using                                                               105        2                                               12   A as reactive monomer                                                     Example                                                                             Process of this invention using                                                               88         3                                               13   a mixture of A and MMA as                                                      reactive monomer                                                          Example                                                                             Process of this invention using                                                               101        2                                               14   B as reactive monomer                                                     Example                                                                             Process of this invention using                                                               97         4                                               15   C as reactive monomer                                                     Example                                                                             Process of this invention using                                                               98         5                                               16   D as reactive monomer                                                     Com- Bulk polymerization                                                                           98         100                                             parative                                                                       Example                                                                        __________________________________________________________________________      Note:                                                                          *.sup.1 Based on 100 parts of charged CF                                 

EXAMPLE 17

Electrolytic polymerization was conducted in the same manner as in Example 12 but using different kinds of CF. Results of evaluating the product compositions are shown in Table 10.

                                      TABLE 10                                     __________________________________________________________________________                   Average                                                                               Amount of                                                                              Percentage of                                              Nature                                                                              diameter of                                                                           polymer deposit                                                                        polymer extreated                                 Run      of   monofilament                                                                          on CF   with chloroform                                   No.                                                                               CF    fiber                                                                               (μ) (parts) for 24 hours                                      __________________________________________________________________________     1  From pitch                                                                           Carbo-                                                                              12.5   109     2                                                          naceous                                                               2  "     Graphitic                                                                           "      100     3                                                 3  From PAN                                                                             Carbo-                                                                              "      105     2                                                          naceous                                                               4  "     Graphitic                                                                           "      102     5                                                 __________________________________________________________________________      Conditions of electrolytic polymerization:                                     CF, 0.123 part; sodium nitrate, 2.5 parts;                                     BRL4290, 50 parts; DMF, 500 parts                                        

As can be seen from Table 10, in the process of this invention, no dependency on the kind of CF was observed of polymerization activity, amounts of polymer deposit on CF were generally satisfactory, and percentages of polymer extracted from the product compositions were low, that is, most of the polymers were firmly bonded to CF without being extracted.

EXAMPLE 18

Electrolytic polymerization was conducted in the same manner as in Example 13 but using each of the monomers shown in Table 11, as a reactive monomer copolymerizable with the alicyclic epoxy compound. Results of evaluating the product compositions are shown in Table 11.

                                      TABLE 11                                     __________________________________________________________________________               Amount of                                                                            Supporting       Polarity of                                                                          Amount of                                  Re-    reactive                                                                             electrolyte      CF during                                                                            polymer                                    active comonomer                                                                            Sodium                                                                               PAN-  Solvent                                                                             electrolytic                                                                         deposit on                                 comono-                                                                               added nitrate                                                                              derived CF                                                                           DMF  polymeriza-                                                                          CF                                      No.                                                                               mer    (parts)                                                                              (parts)                                                                              (part)                                                                               (parts)                                                                             tion  (parts)                                 __________________________________________________________________________     1  MMA    25    2.5   0.123 500  anode 125                                     2  ST     "     "     "     "    "     103                                     3  Vinyl  "     "     "     "    "     110                                        acetate                                                                     4  BuA    "     "     "     "    "     117                                     5  MAA    "     "     "     "    "     115                                     6  GMA/MAA                                                                               "     "     "     "    "     140                                     7  GMA/BuA                                                                               "     "     "     "    "     135                                     __________________________________________________________________________

As is evident from Table 11, any usual vinyl monomer radical-polymerizable can be used as a reactive comonomer in this invention.

EXAMPLE 19

A roving (0.123 g) of PAN-derived CF (HT, made by Mitsubishi Rayon Co., Ltd.) was immersed in a solution prepared by dissolving 250 g of sodium nitrate as a supporting electrolyte in 500 g of demineralized water. After being thoroughly dried, the treated CF was all immersed in an electrolytic solution (50 g of ERL-4299 in 500 g of DMF) contained in the reactor of the same electrolytic polymerization apparatus as used in Example 12. Then, direct current from the D.C. generator was flowed between the CF as anode and the electrolytic solution, thereby carrying out the electrolytic polymerization at room temperature for one hour. During the electrolysis, the current density was adjusted to 0.27 A/dm² by means of the rheostat.

The product composition was evaluated in the same manner as in Example 12. The results showed that the amount of polymer deposited on the CF was 80 parts per 100 parts of CF and the polymer produced from the reactive monomer was bonded uniformly and firmly to the CF surface.

EXAMPLE 20

A unidirectional composite was prepared from a CF-polymer composition obtained from a mixture of 1,000 parts of a reactive monomer ERL-4299, 24.6 parts of CF, 50 parts of sodium nitrate and 100,000 parts of DMF according to the present invention and a general-purpose epoxy resin of bisphenol A type, and was measured for its mechanical properties such as strand strength, inter-laminar shear strength, and flexural strength. For comparison, another unidirectional composite (simple blend) was similarly prepared by using untreated CF and evaluated. Results are shown in Table 12.

                  TABLE 12                                                         ______________________________________                                                       Mechanical properties                                                                 Inter-*.sup.1                                                                  laminar                                                                 Strand shear     Flexural*.sup.1                                               strength                                                                              strength  strength                                                      kg/mm.sup.2                                                                           kg/mm.sup.2                                                                              kg/mm.sup.2                                     ______________________________________                                         Blend of the CF-polymer                                                                        428      11.80     193.3                                       composition of this                                                            invention with epoxy                                                           resin                                                                          Simple blend of CF                                                                             365       7.50     152.0                                       with epoxy resin                                                               ______________________________________                                          *.sup.1 CF content, 60 vol. %                                            

Table 12 indicates that the CF-polymer composition of this invention exhibits excellent mechanical properties in practical applications.

EXAMPLES 21-22 AND COMPARATIVE EXAMPLES 9-11

A roving of PAN-derived high-tenacity CF was set in the reactor of an electrolytic polymerization apparatus, as shown in the drawing, provided with electrode rollers and guide rollers. An electrolytic solution prepared by dissolving 50 g of isopropoxytitanium triisostearate (TTS, made by Toyo Soda Co., Ltd.) as an organic titanate and 25 g of sodium nitrate as a supporting electrolyte in 500 g of DMF was poured into the reactor to immerse the CF roving.

Then, the electrolytic polymerization was effected at room temperature for one hour by flowing direct current between the CF as anode and the electrolytic solution from a D.C. generator. During the electrolysis, the current density was adjusted to 0.27 A/dm² by means of a rheostat.

The product roving was thoroughly washed with DMF and dried in a stream of 100° C. hot air. Then, the binding state of the CF and the amount of polymer deposited on the CF were examined, where the latter was determined by weighing.

The above procedure was repeated by using a mixture of TTS and 25 g of MMA.

For comparison, the above procedure was further repeated by using separately MMA, which is a usual vinyl monomer; tetrapropyltitanium, which is an organo titanium compound having no alkoxyl group; and a mixture of MMA and tetrapropyltitanium; as a reactive monomer. These products were similarly examined. Results thereof are shown in Table 13.

As is evident from Table 13, the CF binding state is inferior and the amount of polymer deposited on CF is extremely limited, in Comparative Examples 9, 10, and 11; in contrast to this, an excellent CF binding state and a much increased amount of polymer deposit are obtained, according to the process of this invention, thus markedly improving the practicality.

                                      TABLE 13                                     __________________________________________________________________________                                       Reduction product*.sup.1                            Reactive monomer                                                                               Supporting     Amount of*.sup.3                                (parts)         electrolyte    polymer                                                Tetra-   Sodium                                                                               Solvent                                                                             CF*.sup.2                                                                          deposited                                              propyl-                                                                             CF  nitrate                                                                              DMF  binding                                                                            on CF                                           TTS                                                                               MMA titanium                                                                            (part)                                                                             (parts)                                                                              (parts)                                                                             state                                                                              (parts)                                  __________________________________________________________________________     Example                                                                               50 --  --   0.123                                                                              2.5   500  ⊚                                                                   82                                       21                                                                             Example                                                                               25 25  --   "   "     "    ⊚                                                                   70                                       22                                                                             Comparative                                                                           -- 50  --   "   "     "    X   5                                        Example 9                                                                      Comparative                                                                           -- --  50   "   "     "    XX  0                                        Example 10                                                                     Comparative                                                                           -- 25  25   "   "     "    XX  3                                        Example 11                                                                     __________________________________________________________________________      Notes:                                                                         *.sup.1 Reaction conditions                                                    Temperature: 25° C.                                                     CF polarity: Positive (anode)                                                  Current density: 0.27 A/dm.sup.2                                               Voltage: 20 V                                                                  Period of electrolysis: 60 minutes                                             *.sup.2 CF binding state                                                       ⊚ very good                                                     X inferior                                                                     XX much inferior                                                               *.sup. 3 Based on 100 parts of charged CF.                               

EXAMPLES 23-25

Polymerization was conducted in the same manner as in Example 21 but using separately tetrastearyl titanate (TST), tetraoctyl titanate (TOT), and tetra-n-butyl titanate [B-1(TBT)] (all made by Toyo Soda Co., Ltd.) as an reactive monomer in place of TTS, and amounts of polymer deposits on CF were examined. Results thereof together with those of Example 21 are shown in Table 14.

                                      TABLE 14                                     __________________________________________________________________________                        Supporting                                                                     electrolyte                                                                               Amount of                                        Reactive monomer   Sodium                                                                               Solvent                                                                             polymer deposit                                  Organic   Amount                                                                              CF  nitrate                                                                              DMF  on CF                                            titanate  (parts)                                                                             (part)                                                                             (parts)                                                                              (parts)                                                                             (parts)                                          __________________________________________________________________________     Example 21                                                                           TTS*.sup.2                                                                         50   0.123                                                                              2.5   500  82                                               Example 23                                                                           TST*.sup.3                                                                         "    "   "     "    77                                               Example 24                                                                           TOT*.sup.4                                                                         "    "   "     "    71                                               Example 25                                                                           B-1*.sup.5                                                                         "    "   "     "    65                                                     (TBT)                                                                    __________________________________________________________________________      Notes:                                                                         *.sup.1 Based on 100 parts of charged CF.                                      ##STR20##                                                                      *.sup.3 TST: Ti(OC.sub.17 H.sub.35).sub.4                                      ##STR21##                                                                                                                                                     *.sup.5 B1(TBT): Ti(On.C.sub.4 H.sub.9).sub.4                            

As can be seen from Table 14, the amount of polymer deposited on CF was on high levels for all the organic titanates.

Then, the percentage of polymer extraction was determined on the CF-polymer compositions obtained in Examples 21-25, by weighing out about 0.1 g of each composition together with a cylindrical filter paper and subjecting the composite sample to Soxhlet extraction with chloroform for 24 hours. Results of the tests are shown in Table 15. Therefrom it has proved that the polymers in the compositions obtained by the process of this invention are for the most part bonded firmly to CF without being extracted.

                  TABLE 15                                                         ______________________________________                                                 Amount of poly-*.sup.1                                                                     Percentage of polymer                                              mer deposit on                                                                             extracted with chloro-                                             CF          form for 24 hours                                                  (parts)     (%)                                                        ______________________________________                                         Example 21                                                                               82            6                                                      Example 22                                                                               70            8                                                      Example 23                                                                               77            7                                                      Example 24                                                                               71            8                                                      Example 25                                                                               65            9                                                      ______________________________________                                          Note:                                                                          *.sup.1 Based on 100 parts of charged CF                                 

EXAMPLE 26

Electrolytic polymerization was conducted in the same manner as in Example 21 but using different kinds of CF. Results of evaluating the product compositions are shown in Table 16.

                  TABLE 16                                                         ______________________________________                                                               Average                                                                               Amount of*.sup.1                                                                        Percentage of                                                  diameter                                                                              polymer  polymer ex-                                           Nature   of mono-                                                                              deposited                                                                               tracted with                             Run          of       filament                                                                              on CF    chloroform                               No.  CF      fiber    (μ) (parts)  for 24 hours                             ______________________________________                                         1    From    Carbon-  12.5   85       7                                             pitch   aceous                                                            2    From    Graphitic                                                                               "      70       9                                             pitch                                                                     3    From    Carbon-  "      82       6                                             PAN     aceous                                                            4    From    Graphitic                                                                               "      78       9                                             PAN                                                                       ______________________________________                                          Note:                                                                          *.sup.1 Conditions of electrolytic polymerization:                             CF, 0.123 part; sodium nitrate, 2.5 parts; TTS, 50 parts; DMF, 500 parts 

As is evident from Table 16, in the process of this invention, no dependency of the kind of CF was observed of polymerization activity, amounts of polymer deposited on CF were generally satisfactory, and percentages of polymer extracted from the product compositions were low indicating that most of the polymers were firmly bonded to CF without being extracted.

EXAMPLE 27

Electrolytic polymerization was conducted in the same manner as in Example 22 but using 25 g of the organic titanate and 25 g each of the comonomers shown in Table 17 as a reactive monomer copolymerizable with the organic titanate. Results of evaluating the product compositions are shown in Table 17.

                                      TABLE 17                                     __________________________________________________________________________                    Supporting       Polarity of                                                                          Amount of                                               electrolyte      CF during                                                                            polymer                                                 Sodium                                                                               PAN-  Solvent                                                                             electrolytic                                                                         deposit                                     Reactive                                                                              Amount                                                                              nitrate                                                                              derived CF                                                                           DMF  polymeriza-                                                                          on CF                                    No.                                                                               comonomer                                                                             (parts)                                                                             (parts)                                                                              (part)                                                                               (parts)                                                                             tion  (parts)                                  __________________________________________________________________________     1  MMA    25   2.5   0.123 500  anode 89                                       2  ST     "    "     "     "    "     67                                       3  Vinyl  "    "     "     "    "     74                                          acetate                                                                     4  BuA    "    "     "     "    "     81                                       5  MAA    "    "     "     "    "     79                                       6  GMA/MAA                                                                               "    "     "     "    "     104                                      7  GMA/BuA                                                                               "    "     "     "    "     99                                       __________________________________________________________________________

As is evident from Table 17, any usual vinyl monomer radical-polymerizable can be used as a reactive comonomer in this invention.

EXAMPLE 28

A roving (0.123 g) of PAN-derived CF was immersed in a solution prepared by dissolving 250 g of sodium nitrate as a supporting electrolyte in 500 g of demineralized water. After being thoroughly dried, the treated CF was all immersed in an electrolytic solution (TTS in 500 g of DMF) contained in the reactor of the same electrolytic polymerization apparatus as used in Example 21. Then, direct current from the D.C. generator was flowed between the CF as anode and the electrolytic solution, thereby carrying out the electrolytic polymerization at room temperature for one hour. During the electrolysis, the current density was adjusted to 0.27 A/dm² by means of the rheostat.

The product composition was evaluated in the same manner as in Example 21. The results showed that the amount of polymer deposited on the CF was 71 parts per 100 parts of CF and the polymer was bonded uniformly and firmly to the CF surface.

The thus obtained CF-polymer composition was extended into a sheet so as to align unidirectionally and was impregnated with a general-purpose epoxy resin of bisphenol A type. The resulting composite sheet was shaped into test pieces, which were then measured for mechanical properties such as strand strength, interlaminar shear strength, and flexural strength. For comparison, another composite sheet (simple blend) was similarly prepared by using untreated CF and evaluated. Results are shown in Table 18.

                  TABLE 18                                                         ______________________________________                                                       Mechanical properties                                                                 Inter-*.sup.1                                                                  laminar                                                                 Strand shear     Flexural*.sup.1                                               strength                                                                              strength  strength                                                      kg/mm.sup.2                                                                           kg/mm.sup.2                                                                              kg/mm.sup.2                                     ______________________________________                                         Blend of the CF-polymer                                                                        419      11.00     190.0                                       composition of this                                                            invention with epoxy                                                           resin                                                                          Simple-blend of CF                                                                             365       7.50     152.0                                       with epoxy resin                                                               ______________________________________                                          *.sup.1 CF content 60 Vol %                                              

Table 18 indicates that the CF-polymer composition of this invention exhibits excellent mechanical properties in practical applications.

EXAMPLES 29-30 AND COMPARATIVE EXAMPLES 13-15

A roving of PAN-derived high-tenacity CF (made by Mitsubishi Rayon Co., Ltd.) was set in the stainless steel reactor of an electrolytic polymerization apparatus, as shown in the drawing, provided with copper electrode rollers and glass guide rollers. An electrolytic solution prepared by dissolving 50 g of vinyl-tris(β-methoxyethoxy)silane (KBC 1003, made by Shinetsu Chem. Ind. Co., Ltd.) as a vinylsilane compound and 25 g of sodium nitrate as a supporting electrolyte in 500 g of DMF was poured into the reactor to immerse the CF roving.

Then, direct current from a D.C. generator was flowed between the CF as anode and the electrolytic solution, thereby carrying out the electrolytic polymerization at room temperature for one hour. During the electrolysis, the current density was adjusted to 0.27 A/dm² by means of a rheostat.

The product roving was throughly washed with DMF and dried in a stream of 100° C. hot air. Then the binding state of the CF and the amount of polymer deposited on the CF were examined, where the latter was determined by weighing.

The above procedure was repeated by using mixture of 25 g of KBC 1003 and 25 g of MMA. For comparison, the above procedure was further repeated by using separately MMA, which has no silicon atom; trimethylethoxysilane, which is a saturated silane having no double bond; and a mixture of MMA and trimethylethoxysilane; as a reactive monomer. These products were similarly examined. Results thereof are shown in Table 19.

As is evident from Table 19, saturated silane as used in Comparative Example 14 exhibits no polymerization activity; when MMA used singly as in Comparative Example 13, the CF binding state is considerably inferior and the amount of polymer deposited on the CF is extremely limited; in contrast, according to the process of this invention, an excellent CF binding state and a much increased amount of polymer deposited on CF are obtained, thus markedly improving the practical value.

                                      TABLE 19                                     __________________________________________________________________________            Reactive monomer              Reaction product*.sup.6                          (parts)            Supporting     Amount of*.sup.8                                       Tri-*.sup.3                                                                             electrolyte    polymer                                                methyl-  Sodium                                                                               Solvent                                                                             CF*.sup.7                                                                          deposited                                    KBC-*.sup.1                                                                              ethoxy-                                                                             CF*.sup.4                                                                          nitrate                                                                              DMF*.sup.5                                                                          binding                                                                            on CF                                        1003 MMA*.sup.2                                                                          silane                                                                              (part)                                                                             (parts)                                                                              (parts)                                                                             state                                                                              (parts)                               __________________________________________________________________________     Example 29                                                                            50   --   --   0.123                                                                              2.5   500  ⊚                                                                   58                                    Example 30                                                                            25   25   --   "   "     "    ⊚                                                                   55                                    Comparative                                                                           --   50   --   "   "     "    X   7                                     Example 13                                                                     Comparative                                                                           --   --   50   "   "     "    X   1                                     Example 14                                                                     Comparative                                                                           --   25   25   "   "     "    X   3                                     Example 15                                                                     __________________________________________________________________________      Notes:                                                                         *.sup.1 Vinyltris (β-methoxyethoxy) silane (a vinylsilane, made by        Shinetsu Chem. Ind. Co., Ltd.)                                                 *.sup.2 MMA: Methyl methacrylate                                               *.sup.3 A saturated silane                                                     *.sup.4 A roving of PANderived hightenacity CF (made by Mitsubishi Rayon       Co., Ltd.)                                                                     *.sup.5 DMF: N,N--Dimethylformamide                                            *.sup.6 Reaction conditions                                                    Temperature: 25° C.                                                     CF polarity: Positive (anode)                                                  Current density: 0.27 A/dm.sup.2                                               Voltage: 20 V                                                                  Period of electrolysis: 60 minutes                                             *.sup.7 CF binding state                                                       ⊚ very good                                                     X inferior                                                                     XX much inferior                                                               *.sup.8 Based on 100 parts of charged CF                                 

EXAMPLES 31-35

Electrolytic polymerization was conducted in the same manner as in Example 29 but using separately vinyltriethoxysilane, γ-methacryloxypropyl trimethoxysilane, vinyltripropoxysilane, vinyl-tris(β-methoxypropoxy)silane, and γ-methacryloxybutyltrimethoxysilane as a reactive monomer in place of vinyl-tris(β-methoxyethoxy)silane, and amounts of polymer deposited on CF were examined. Results thereof are shown in Table 20 comparing with those of Example 29.

                                      TABLE 20                                     __________________________________________________________________________                            Supporting Amount of                                                           electrolyte                                                                               polymer                                      Reactive monomer       Sodium                                                                               Solvent                                                                             deposited                                                  Amount                                                                              CF  nitrate                                                                              DMF  on CF                                        Vinylsilane   (parts)                                                                             (parts)                                                                            (parts)                                                                              (parts)                                                                             (parts)                                      __________________________________________________________________________     Example                                                                             Vinyl-tris(β-                                                                      50   0.123                                                                              2.5   500  58                                           29   methoxyethoxy)-                                                                silane                                                                    Example                                                                             Vinyltriethoxy-                                                                         "    "   "     "    50                                           31   silane                                                                    Example                                                                             γ-Methacryloxy-                                                                   "    "   "     "    52                                           32   propyltrimethoxy-                                                              silane                                                                    Example                                                                             Vinyl-tripropoxy-                                                                       "    "   "     "    32                                           33   silane                                                                    Example                                                                             Vinyl-tris(β-                                                                      "    "   "     "    42                                           34   methoxypropoxy)-                                                               silane                                                                    Example                                                                             γ-Methacryloxy-                                                                   "    "   "     "    28                                           35   butyltrimethoxy-                                                               silane                                                                    __________________________________________________________________________      *.sup.1 Based on 100 parts of charged CF                                 

As shown in Table 20, the amount of polymer deposited on CF was fairly large for vinyl-tris(β-methoxyethoxy)-silane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane and on somewhat lower levels for vinyltripropoxysilane and γ-methacryloxybutyltrimethoxysilane.

Then, the percentage of polymer extraction was determined on the CF-polymer compositions obtained in Examples 29-35, by weighing out about 0.1 g of each composition together with a cylindrical filter paper and subjecting the composition sample to Soxhlet extraction with chloroform for 24 hours. For comparison, the same test was conducted on a composition (Comparative Example 16) prepared by a bulk polymerization in the presence of the same CF roving using a common radical polymerization initiator. Results of these tests are shown in Table 21. Therefrom it has proved that, while the polymer in the composition of Comparative Example 16 is completely extracted during 24 hours, the polymer of the composition obtained by the process of this invention is scarcely extracted, that is, most of the polymer is firmly bonded to the CF without being extracted.

                                      TABLE 21                                     __________________________________________________________________________                          Amount of polymer*.sup.2                                                                  Percentage of polymer                                               deposited on CF                                                                           extracted with chloro-                         Polymerization process                                                                              (parts)    form for 24 hours                              __________________________________________________________________________     Example                                                                             Process of this invention,                                                                     58         5                                              29   Reactive monomer: Vinyl-                                                       tris(β-methoxyethoxy)silane                                          Example                                                                             Process of this invention,                                                                     55         6                                              30   Reactive monomer: Mixture of                                                   vinyl-tris(β-methoxyethoxy)-                                              silane and MMA                                                            Example                                                                             Process of this invention,                                                                     50         5                                              31   Reactive monomer: Vinyltri-                                                    ethoxysilane                                                              Example                                                                             Process of this invention                                                                      52         5                                              32   Reactive monomer: γ-Methacryl-                                           oxypropyltrimethoxysilane                                                 Example                                                                             Process of this invention                                                                      32         8                                              33   Reactive monomer: Vinyl-                                                       tripropoxysilane                                                          Example                                                                             Process of this invention,                                                                     42         7                                              34   Reactive monomer: Vinyl-                                                       tris(β-methoxypropoxy)silane                                         Example                                                                             Process of this invention,                                                                     28         9                                              35   Reactive monomer: γ-Methacryl-                                           oxybutyl trimethoxysilane                                                 Com- Bulk polymerization process                                                                    85         100                                            parative                                                                            Initiator: AIBN*.sup. 1                                                   Example                                                                        16                                                                             __________________________________________________________________________      *.sup.1 AIBN: Azoisobutyronitrile                                              *.sup.2 Based on 100 parts of charged CF.                                

EXAMPLE 36

Electrolytic polymerizatiom was conducted in the same manner as in Example 29 but using different kinds of CF. Results of evaluating the product compositions are shown in Table 22.

                                      TABLE 22                                     __________________________________________________________________________                      Average                                                                        diameter                                                                            Amount of*.sup.3                                                                        Percentage of                                             Nature of mono-                                                                            polymer deposited                                                                       polymer extracted                                         of     filament                                                                            on CF    with chloroform                                 No.                                                                               CF     fiber  (μ)                                                                              (parts)  for 24 hours                                    __________________________________________________________________________     1  From pitch*.sup.1                                                                     Carbonaceous                                                                          12.5 59       5                                                  (T-101S)                                                                    2  From pitch*.sup.1                                                                     Graphitic                                                                             "    55       7                                                  (T-201S)                                                                    3  From Pan*.sup.2                                                                       Carbonaceous                                                                          "    58       5                                                  (HT)                                                                        4  From Pan*.sup.2                                                                       Graphitic                                                                             "    57       8                                                  (HM)                                                                        __________________________________________________________________________      Notes:                                                                         *.sup.1 Tradename: Kurekatow, made by Kureha Chem. Ind. Co., Ltd.              *.sup.2 Made by Mitsubishi Rayon Co., Ltd.                                     *.sup.3 Conditions of electrolytic polymerization. CF, 0.123 part; DMF,        500 parts; NaNO.sub.3, 25 parts; Vinyltris(β-methoxyethoxy)silane, 5      parts.                                                                   

As can be seen from Table 22, in the process of this invention, no dependency on the kind of CF was observed of polymerization activity, amounts of polymer deposited on CF were generally satisfactory, and percentages of polymer extracted from the product compositions were low, indicating that most of the polymers were firmly bonded to CF without being extracted.

EXAMPLE 37

Electrolytic polymerization was conducted in the same manner as in Example 29 but using 25 g of the vinylsilane compound and 25 g each of the monomers shown Table 23 as a reactive comonomer copolymerizable with the vinylsilane compound. Results of evaluating the product compositions are shown in Table 23.

                                      TABLE 23                                     __________________________________________________________________________                                      Polarity                                                                            Amount of                                          Amount of                                                                            Supporting       of CF                                                                               polymer                                            comonomer                                                                            electrolyte                                                                          PAN-  Solvent                                                                             during                                                                              deposited                                   Reactive                                                                              added NANO.sub.3                                                                           derived CF                                                                           DMF  electro-                                                                            on CF                                    No.                                                                               comonomer                                                                             (parts)                                                                              (parts)                                                                              (part)                                                                               (parts)                                                                             lysis                                                                               (parts)                                  __________________________________________________________________________     1  MMA    25    2.5   0.123 500  anode                                                                               50                                       2  ST     "     "     "     "    "    28                                       3  Vinyl acetate                                                                         "     "     "     "    "    35                                       4  BuA    "     "     "     "    "    42                                       5  MAA    "     "     "     "    "    40                                       6  GMA/MAA                                                                               "     "     "     "    "    65                                       7  GMA/BuA                                                                               "     "     "     "    "    60                                       __________________________________________________________________________

As is evident from Table 23, any usual vinyl monomer radical-polymerizable can be used as a reactive comonomer in this invention.

EXAMPLE 38

A roving (0.123 g) of PAN-derived CF (HT, made by Mitsubishi Rayon Co., Ltd.) was immersed in a solution prepared by dissolving 250 g of sodium nitrate as a supporting electrolyte in 500 g of demineralized water. After being thoroughly dried, the treated CF was all immersed in an electrolytic solution [50 g of vinyl-tris(β-methoxyethoxy)silane in 500 g of DMF] contained in the reactor of the same electrolytic polymerization apparatus as used in Example 29. Then, direct current from the D.C. generator was flowed between the CF as anode and the electrolytic solution, thereby carrying out the electrolytic polymerization at room temperature for one hour. During the electrolysis, the current density was adjusted to 0.27 A/dm² by means of the rheostat.

The product composition was evaluated in the same manner as in Example 29. The results showed that the amount of polymer deposited on the CF was 52 parts per 100 parts of CF and the polymer was bonded uniformly and firmly to the CF surface.

EXAMPLE 39

A unidirectional composite was prepared from the CF-polymer composition obtained from a mixture of 1,000 parts of KBC 1003 [vinyltris(β-methoxyethoxy)silane], 24.6 parts of CF, 50 parts of sodium nitrate and 100,000 parts of DMF according to the present invention and a general-purpose epoxy resin of bisphenol A type, and was shaped into test pieces, which were then measured for mechanical properties such as strand strength, interlaminar shear strength, and flexural strength. For comparison, another composite sheet (simple blend) was similarly prepared by using untreated CF and evaluated. Results are shown in Table 24.

                  TABLE 24                                                         ______________________________________                                                       Mechanical properties                                                                 Inter-*.sup.1                                                                  laminar                                                                 Strand shear     Flexural*.sup.1                                               strength                                                                              strength  strength                                                      kg/mm.sup.2                                                                           kg/mm.sup.2                                                                              kg/mm.sup.2                                     ______________________________________                                         Blend of the CF-polymer                                                                        398      9.88      187.6                                       composition of this                                                            invention with epoxy                                                           resin                                                                          Simple blend of CF                                                                             340      7.30      148.1                                       with epoxy resin                                                               ______________________________________                                          *.sup.1 CF content 60 Vol. %                                             

Table 24 indicates that the CF-polymer composition of this invention exhibits excellent mechanical properties in practical use.

EXAMPLE 40

Electrolytic polymerization was conducted in the same manner as in Example 1 or 12 but by using CF's which were defferent in average diameter of monofilament as shown in Table 25. Results of evaluating the resulting compositions are shown in Table 25. The results have revealed that the use of very fine CF further improves the CF binding state and markedly increases the amount of polymer deposited on CF.

                                      TABLE 25                                     __________________________________________________________________________                               Reaction product                                     CF                              Amount of polymer                              Average diameter                                                                               Reactive monomer                                                                               deposited on CF (parts                            of monofilament                                                                             Denacol                                                                             ERL- CF-binding                                                                           per 100 parts of                               No.                                                                               (μm)  (part)                                                                             EX-821                                                                              4299 state charged CF)                                    __________________________________________________________________________     1  2.0      0.123                                                                              50 parts                                                                            --   ⊚                                                                     220                                            2  3.0      "   "    --   ⊚                                                                     180                                            3  5.0      "   "    --   ⊚                                                                     163                                            4  2.0      "   --   50 parts                                                                            ⊚                                                                     280                                            5  3.0      "   --   "    ⊚                                                                     263                                            6  5.0      "   --   "    ⊚                                                                     235                                            __________________________________________________________________________ 

What is claimed is:
 1. A process for producing a polymer composition, wherein an organic polymer is strongly bonded to carbon fiber, by the electrolytic polymerization of a reactive monomer using the carbon fiber as an electrode, the reactive monomer comprising an aliphatic epoxy compound, alicylic epoxy compound, or vinylsilane compound, as a part or all of the reactive monomer.
 2. The process for producing a polymer composition according to claim 1, wherein (I) the aliphatic epoxy compound is a bifunctional epoxy compound represented by the general formula ##STR22## wherein R₁, R₂, R₃, and R₄ each represent hydrogen, C₁ -C₂₀ alkyl, phenyl, substituted phenyl having C₁ -C₂₀ alkyl, or halogen and n represents an integer of 0-50; and (2) the alicylic epoxy compound is a bifunctional epoxy compound represented by the general formula ##STR23## wherein; R₅ represents a residue of the formula ##STR24## where R₇ is C₁ -C₂₀ alkylene; and R₆ represents C₁ -C₃₀ alkylene; or by the general formula ##STR25## wherein R₈ represents C₁ -C₃₀ alkylene.
 3. The process for producing a polymer composition according to claim 2, wherein the aliphatic epoxy compound is represented by the general formula [I] in which n is an integer of 0-20.
 4. A process for producing a polymer composition, wherein an organic polymer is strongly bonded to carbon fiber, by the electrolytic polymerization of a reactive monomer using the carbon fiber as an electrode, the reactive monomer comprising an organic titanate compound represented by

    the general formula Ti(O--R.sub.9).sub.4                   [IV]

wherein R₉ represents C₁ -C₅₀ alkyl, or by the general formula ##STR26## wherein R₁₀ represents hydrogen or C₁ -C₄₀ alkyl and R11 represents C₁ -C₄₀ alkyl as a part or all of the reactive monomer.
 5. The process for producing a polymer composition according to claim 1, wherein the vinylsilane compound is represented by the general formula ##STR27## wherein; R₁₂ represents hydrogen, C₁ -C₂₀ alkyl, phenyl, substituted phenyl having C₁ -C₂₀ alkyl, or halogen; R₁₃ represents a residue of the formula (CH₂)_(m) or COO(CH₂)_(Q), where m is an integer of 0-30 and Q is an integer of 0-20; and R₁₄ represents C₁ -C₁₅ alkyl or a residue of the formula --Y--O--Z, where Y is C₁ -C₁₅ alkylene and Z is C₁ -C₁₅ alkyl. 